Freak Felids - A Discussion of History's Largest Felines

[tigerluver]

(05-18-2021, 11:58 PM)Sully Wrote: @tigerluver I was wondering if you have any thoughts on post #1152, the new 400kg+ cat machairodus lahayishupup. Could this really rival the likes of populator, ngandong, fossilis etc?

It's certainly an intriguing candidate in the size department. To preface, here are the key measurement and formula information that produced the weights.

The humerus is the longest I've read of. The authors mention it is narrow in articular width which would lighten it up a bit. However, it's unclear where the conclusion comes from as if we compare to Peigne et al. (2005), it's more robust than the Amphimachairodus and about the same as a tiger/lion (TL/MWDH of 3.73, the lower the number the more robust the humerus distally):

*This image is copyright of its original author

Similarly, if we compare the articular width to the cats in Christiansen and Harris (2005), it's again like that of lions and tigers. I may have missed something in the descriptive paper but if so I cannot find it.

So in simple terms, we could probably have a decent estimate by taking the articular length of the humerus (438 mm) and using isometry against lions and tigers, the lower of which (based on the longer leg to spine length lion) is 350 kg and upper of which (based on the longer spine to leg length tiger) is 450 kg. The reason why the estimate differ is due to the spine proportions. Lions are lighter for their leg length because they have a shorter spine per unit leg length and also have a longer cervical and thoracic region (thus shorter lumbar region). The lumbar region is the most dense given the musculature and guts), while the thoracic region has more airspace (less density), and the cervical region has much less weight per unit length as compared to the other regions because the neck is much narrower than the chest/abdomen. Therefore, the tiger is not only longer per unit leg length but also is composed of more of the lumbar region, giving it a higher weight per unit leg length.

The thing about Machairodus is that a very large proportion of its spine is dedicated to the neck and and based on New World Machairodus the lumbar region is even shorter than that in the lion. This would mean Machairodus would at best have a weight to leg length ratio like that of the lion, but likely less in reality. As such, this new giant is probably 350 kg or a bit less. This is comparable to most of the ancient giants but probably is just a bit lighter than S. populator, some ancient lions, and the Late Pleistocene tiger. In terms of frame however, this specimen may be the largest we know of from the cat family. Reply